The field of the disclosure relates generally to detecting loss of phase, and more specifically, to circuits and methods for detecting loss of phase in three-phase power systems using current measurements of each independent phase.
Three-phase power sources are used in numerous varieties and applications worldwide. For example, at least some heating, ventilation, and air conditioning (HVAC) systems and three-phase motors are powered by three-phase power sources. Detecting loss of phase and power imbalance in three-phase power sources is vital in operating three-phase power systems to reduce wear and prevent equipment overheating and shut down.
Known three-phase power systems generally utilize voltage monitoring for loss of phase detection. Voltage monitoring typically focuses on the amplitude of the voltage provided by each phase. Phase imbalance and distortion generally cannot be detected, and power and efficiency generally cannot be calculated from amplitude measurements without frequency or period measurements. Further, a high voltage line of the three-phase power source is generally directly attached to a microprocessor that processes the voltage measurements. In such configurations, a surge in voltage in the system can overload and damage the microprocessor, rendering the microprocessor inoperable and unable to process the voltage measurements.